The Minolta Spectrophotometer (Model CM-2002), also referred to as the Minolta Color Scanner, is a handheld instrument that measures color reflectance over a spectral range of 400 to 700 nm wavelengths. The instrument was commonly used on ODP Legs and some IODP expeditions, either in handheld mode or as part of an automated track system in which the instrument was moved along the track and lowered onto a split-core section for making measurements (Figure 1).
Figure 1. Taking measurements.
Instrument Configuration
The Minolta Spectrophotometer comes in a case, which should contain all components necessary to run, except a lap top (Figure 2).. The necessary components for use with Spectrolog software are
To use the scanner with the Spectrolog software, connect a RS232 null modem cable to the Minolta, connect the RS232 end of a National Instruments RS232-to-USB cable to the null modem cable and connect the USB end to a computer, preferably a lap top for mobility, and plug in the power supply. The internal battery will charge but may not retain a charge for the duration of measuring core sections.
Figure 2. Picture of the instrument, cables, and white calibration standard.
Figure 3. Picture of scanner components (front and back).
The Spectrolog software runs the scanner (Figure 3). It is located on a CD that is in the Minolta Spectrophotometer case.
Figure 4. Screen capture of Spectrolog software.
These installation steps will require administrative privilege on the target workstation. Actual operation of the software does NOT require administrative privilege.
Notes:
Figure 5. New Core button screen
Standards should be measured without plastic wrap. Sections are prepare similar to those measured on the SHMSL. For a sediment core, preparation is:
a. IMPORTANT!!! It is necessary to cover the core section with GLAD® PlasticWrap in order to avoid damage to the integration sphere. Any mud that gets on the glass window of the integration sphere or scratches to the glass will prevent accurate measurement of subsequent samples. Care should be taken to reduce wrinkles in the wrap.
Warning! Do not cover the standards with GLAD® Plastic Wrap; they will give erroneous results if you do.
First-time users may find it useful press Control+H to obtain on-line help. Hover over each of the interface elements to see what it does. Control+H again to put away help.
The application is architected to save data to a file named according to the expedition, site, hole, and core specified. As a section is completed, toggle the drop-down list to the next section--data continues to go into the same file. When measurements for a core are completed, press the 'New Core' button to start a new data file.
Acquisition of data to a file may be turned-off by toggling the 'Record data to file' button. This is useful for intermediate control readings.
The measurement progress bar may be reset at any time by clicking on the arrows at the end of the bar. The next measurement taken will have that centimeter interval applied to the reading.
As noted above, calibration is to be completed when you turn the instrument on. Attach the white calibration standard by gently turning it on the integration sphere. Press the measurement button on the scanner. The scanner automatically goes into measurement mode afterwards. To see if the calibration worked, take another measurement while the calibration standard is still on the scanner or measure other standards and compare the observed values to those expected.
Calibration can be complete any time without restarting the scanner by using the menu options of the scanner.
Figure 6. Calibration screen and white calibration standard.
While output for the Minolta Spectrophotometer can be modified as described in the vendor manual, for using the SPECTROLOG software, the output must be set to report XYZ, L*a*b*, and Munsell (hue value chroma--HVC). Program data parser expects to find this info in the output stream. Thus, it is best to leave the settings of the instrument as is. If they are altered, please return them to the Spectrolog settings when done.
When running Spectrolog, the following output is recorded in tab-delimited columns of an ASCII text file:
Expedition, Site, Hole, Core, Core Type, Section, Interval Top (cm), Interval Bottom (cm), "L*a*b*", L*, a*, b*, "XYZ", X, Y, Z, "hvc", Hue, Value, Chroma, "spectra", 400 nm, 410 nm, 420 nm, ..., 690 nm, and 700 nm.
The three columns for "hvc" are the Munsell Hue, Value, and Chroma. The "spectra" is given every 10 nm from 400 to 700 nm.
An example output is shown for 4 measurements along section 384-1554A-5H-5:
384 1554 A 5 H 5 135.0 135.1 L*a*b* 38.45 -1.28 3.25 XYZ 9.67 10.34 10.13 hvc 1.3 GY 3.7/.5 spectra 8.36 8.37 8.58 8.82 9.05 9.23 9.41 9.59 9.76 9.87 9.98 10.12 10.26 10.31 10.36 10.42 10.49 10.58 10.59 10.56 10.51 10.40 10.31 10.21 10.09 9.96 9.81 9.69 9.58 9.45 9.35
384 1554 A 5 H 5 137.5 137.6 L*a*b* 36.19 -1.08 4.83 XYZ 8.53 9.11 8.41 hvc 8.7 Y 3.5/.7 spectra 6.88 6.75 6.86 7.14 7.39 7.63 7.85 8.06 8.25 8.42 8.57 8.74 8.87 8.99 9.06 9.15 9.28 9.40 9.44 9.46 9.42 9.35 9.30 9.23 9.17 9.09 8.99 8.89 8.80 8.75 8.71
384 1554 A 5 H 5 140.0 140.1 L*a*b* 37.08 -0.77 3.63 XYZ 9.01 9.58 9.24 hvc 8.4 Y 3.6/.5 spectra 7.62 7.58 7.75 8.02 8.25 8.42 8.61 8.78 8.90 9.01 9.13 9.27 9.38 9.46 9.54 9.62 9.70 9.83 9.89 9.88 9.85 9.82 9.76 9.67 9.57 9.50 9.40 9.31 9.24 9.15 9.09
384 1554 A 5 H 5 142.5 142.6 L*a*b* 36.95 -0.82 4.08 XYZ 8.94 9.51 9.03 hvc 8.3 Y 3.6/.6 spectra 7.30 7.35 7.48 7.78 8.03 8.24 8.42 8.60 8.74 8.85 9.00 9.17 9.27 9.38 9.46 9.54 9.64 9.78 9.85 9.85 9.82 9.77 9.72 9.62 9.52 9.44 9.34 9.25 9.17 9.06 9.00
384 1554 A 5 H 5 145.0 145.1 L*a*b* 37.69 -0.74 3.99 XYZ 9.33 9.91 9.46 hvc 7.9 Y 3.7/.6 spectra 7.60 7.73 7.91 8.15 8.43 8.63 8.82 8.99 9.14 9.27 9.39 9.55 9.68 9.74 9.83 9.96 10.08 10.18 10.24 10.27 10.25 10.18 10.14 10.05 9.94 9.89 9.81 9.71 9.61 9.52 9.48
384 1554 A 5 H 5 147.5 147.6 L*a*b* 36.98 -0.92 4.19 XYZ 8.95 9.53 9.01 hvc 8.6 Y 3.6/.6 spectra 7.18 7.32 7.46 7.72 8.00 8.22 8.42 8.60 8.74 8.89 9.03 9.16 9.29 9.39 9.48 9.58 9.68 9.82 9.87 9.86 9.84 9.76 9.70 9.62 9.52 9.45 9.34 9.25 9.15 9.05 9.00
Figure 5. Example data plot.
This document was originated on Expedition 384 by Gary Acton (OTHERS ADD NAMES) and includes text from notes written by Bill Mills, who is the author of the Spectrolog software. Credits for subsequent changes to this document are given in the page history.